Work is really eating my time right now, so I have a short and sweet post for you today, which is really just a graphic. A really graphic graphic. Here it is:

Source:

• http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/polio.pdf (it’s their graphic which I redrew to improve clarity)

This work by Dr C M Helm-Clark PhD is licensed under a Creative Commons Attribution 4.0 International